Medication adherence in people of culturally and linguistically diverse backgrounds: a meta-analysis

BACKGROUND: Medication adherence is of particular importance for people of culturally and linguistically diverse (CALD) backgrounds due to language difficulties, lack of social and organizational supports, lack of access to healthcare resources, and disengagement with the health-care system. OBJECTIVE: To evaluate the impact of interventions to improve medication adherence in people of CALD backgrounds through a systematic review and meta-analysis. METHODS: A search was performed using the following databases: Cochrane Database of Systematic Reviews, Cumulative Index to Nursing & Allied Health Literature, EMBASE, Journals@Ovid, PsychInfo, PubMed, Science Direct, Scopus, and Web of Science. Databases were searched from January 1978 to October 2009. RESULTS: Forty-six articles reviewed were assessed as being relevant, which included 36 randomized controlled trials, 2 observational cohort studies, and 8 quasi-experimental studies. The most common method for assessing medication adherence was self-reporting measures, such as the Morisky Scale and its modifications. Few studies used combinations of adherence measures, and adherence involving a medication event monitoring system (MEMS) was used in only 6 studies. Individuals of CALD backgrounds were recruited with people of non-CALD backgrounds and subsequent analyses tended to be undertaken of the whole sample. Twenty studies showed statistically significant improvements in medication adherence, 15 of which were randomized controlled trials. Six of the successful interventions involved delivery by a bilingual person or the use of translated materials and 4 involved the use of a conceptual model. Meta-analyses demonstrated modest improvements in medication adherence. CONCLUSIONS: Relatively little high-quality work has been conducted on adherence-enhancing interventions for people of CALD backgrounds. Greater attention needs to be given to examining the needs of specific CALD population groups. Future researchers should consider rigorously testing interventions that take into account the enormous diversity and differences that exist within any particular CALD group.